This invention relates to a method and system for detecting an obstructing element in the path of an automotive vehicle window. This is accomplished by sensing or observing a system variable, such as speed or motor current, and comparing this measured value to a predicted value of the system variable, which is determined by way of a system equation, in order to determine the presence of an obstructing object.
Vehicles are provided with closures to close openings. Typically, these closures are powered by an electric motor to move between open and closed positions within a frame. Such closures include side windows, moon roofs, sunroofs, etc. Typically, an operator actuates a switch and the closure will move to a fully closed position. In this disclosure, a side window is disclosed. However, it should be understood that the invention applies to all closures, such as moon roofs, sunroofs, etc.
If an object is in the path of the closure, such as a passenger""s arm, the prior art would like closure movement to stop or even be reversed. Thus, various systems have been proposed to monitor characteristics of operation during closure to identify the obstruction. Typically, characteristics of the motor are sensed.
It is known that detailed system equations can identify the presence of an object by looking at a number of system variables. However, such equations are of limited value in that there are too many unknowns which are unique to each closure system. Various aspects such as the particular tolerances within the closure system, temperature, age, etc. affect how each individual system will respond.
Thus, there exists a need for an accurate yet simple algorithmic system for identifying the presence of an object in the path of a vehicle closure.
The present invention observes a system variable, x, such as speed or motor current, to determine the presence of an object. A system equation is used to predict a value of the observed variable as it would normally behave without the presence of an object. This predicted value (xp) is compared to a measured value (xm) of the observed variable. If the measured value (xm) exceeds the predicted value (xp) by some limit, in the direction indicative of an object, then the control system detects an object and reacts accordingly, typically by stopping or reversing the motor.
The present invention also uses a correction mechanism to account for inaccuracies in the system equation. A system equation may not be accurate due to variability between systems and changes due to temperature and aging. In addition, the system equation is adapted over time to also account for these inaccuracies.
These and other features of the present invention can be best understood from the following specification and drawings.